The goal of this research is to elucidate molecular mechanisms by which the gonadotrophin LH influences the functions of luteinizing follicles and corpora lutea. The proposed research is based on 2 findings. (1) An ovulatory dose of hCG promotes desensitization of the LH-sensitive adenylyl cyclase system to stimulation by LH in preovulatory follicles as well as in corpora lutea and, (2) An ovulatory dose of hCG induces changes in the pattern of multiplicity of protein kinases as follicles differentiate into corpora lutea, characterized by the appearance of two seemingly new species of protein kinase activity. We propose to examine the seemingly new species of protein kinase activities in order to determine (1) exactly when during the preovulatory or postovulatory time period and by what mechanism do the protein kinases appear, (2) the degree of selective activation of the two luteal protein kinases during pseudopregnancy and pregnancy, (3) if the luteal-specific protein kinase is functional in LH-mediated steroidogenesis and/or luteolysis, and (4) whether the presence, activity, and responsiveness of the luteal-specific LH-sensitive adenylyl cyclase and protein kinase enzyme systems are regulated by other gonado-hormones.